The present invention relates to a lens assembly installation of scanner, more particularly to all improvement of a light filtering lens assembly in the lens assembly inside the scanner to simplify the structural construction and the transmission method of the whole to achieve the reduction of the production cost.
Referring to FIG. 4, according to the construction of the light filtering lens assembly in the lens assembly of the conventional scanner, it consists of a stepping motor 31, a sectorial lens bracket 35, four pieces of lens and four pieces of metallic lug piece in which the front rim end face appears in a circular arc with four windows 351 provided, the front face of each window 351 is provided with a subsided step face 352 with lug holes 353 and 354 provided one each at the top and bottom rims of the window 351 so that the lens 34 can be placed inside the step face 352 and then hooked into the top and bottom lug holes 353 and 354 on the window 351 with the top and bottom end lugs 361 and 362 of the metallic lug piece 36 respectively and assembled into an integral by virtue of the hold-down plate 363 provided at the mid section of the metallic lug piece 36 pressing on the lens 34. In addition, at the location where the inner side of the support plate 355 is near to the window, an inner toothed gear sector is provided with a shaft hole 357 furnished at the other end and by virtue of this hole, the sectorial lens bracket is fixed onto the slide base. The stepping motor 31 is then fixed to the downside of the shaft hole 357 and drives by gearing between the pinion 312 on top of the motor 31 with the inner toothed gear sector 356 through the idler 313. As the generally known construction mentioned above, there is no way to complete fixing it once when assembling the lens 34. As the requirement for the cleanliness of the lens 34 is extremely high and untouchable by hand and the sizes of the components are very small, therefore it is rather difficult to assemble them and due to the incorporation of the lugs 361 and 362 of the metallic lug piece 36 and lug holes 353 and 354 is a loose fit, the lens 34 still can produce sway and unsteady situation after fixing the whole assembly affecting the quality of the product. So far as the cost is concerned, the commonly known light filtering lens assembly with the construction of an inner toothed gear sector 356 fixed at the inside of its sectorial lens bracket 35 further causes the cost to become higher due to its precision being harder to grasp, the idler 313, pinion 312, metallic lug piece 36, etc., have still to be manufactured and above additional higher difficulty of the relevant procedure of assembly which altogether will create shortcomings like the increase of integral manufacturing cost, being nonbeneficial to industrial competition, etc.